A METHOD AND ARRANGEMENT FOR DRYING WATER-DAMAGE CONCRETE FLOORS OR CONCRETE SUB-FLOORS IN BUILDINGS

Abstract: There is proposed a method for drying a water-damage concrete floor structure or concrete sub-floor (3), which may or may not include an insulating layer (4, 2). According to the invention, an insulating device (7) is placed on the floor surface in spaced relationship therewith so as to form an underlying gap (8). Dry, hot pressurized air is delivered to the gap with the intention of removing moisture-laden air that has diffused up from the water-damaged area. When the sub-floor supports an insulating layer (4) of sand or mineral wool, hot, dry air is also delivered to this layer. The invention also relates to apparatus which operates in accordance with the inventive method.

Description: A METHOD AND ARRANGEMENT FOR DRYING WATER-DAMAGED CONCRETE FLOORS OR CONCRETE SUB-FLOORS IN BUILDINGS TECHNICAL FIELD The present invention relates to a method of drying a water-damaged concrete sub-floor or concrete floor and also a floor insulation when present, wherein dry and hot air is delivered under pressure to the water- damaged area and, saturated with moisture, is permit¬ ted to depart to atmosphere, to an overlying room or an overlying space, or is collected for transportation or treatment and optionally for renewed use. The invention also relates to drying apparatus of the kind defined in the preamble of Claim 7. DESCRIPTION OF THE PRIOR ART Water-damaged floor structures are dried conventional¬ ly with the aid of a suction fan which operates to extract air from the water-damaged area and to eject the air to atmosphere. At the same time, room air flows into said area through inlet openings that are distanced from the area. This technique is described, for instance, in Swedish Patent Specification 0,247,216 (Munters Trocknungs-Service) . Alternatively, the pressure side of the fan can be used to deliver air under pressure to the water- damaged area. SE-B-435,946 (Kullberg) describes a method and appara- tus for drying a concrete sub-floor and associated fill and upper floor surface. There is formed in the upper floor surface a number of small holes into which injection needles are inserted, these needles being connected to a compressed-air source to deliver a stream of compressed air of low absolute humidity and overtemperature in relation to the sub-floor. The primary function of the hot air injected through these needles is to increase the temperature of the sand layer included in the fill, so that the damaged area can be dried without needing to break-up the floor. The floor surface is typically comprised of particle board or parquet boards and between the floor surface and the sub-floor, there is found an equal¬ izing layer of sand, while a diffusion impermeable sheet of material is provided between the sand fill and the upper floor surface. A floor structure of this kind is capable of absorbing significance quantities of water in the event of a water leakage. The concrete slab may be completely drenched with water and water may also be found both beneath and on top of the plate. Placed on the floor is an insulating layer under which the injection needles are inserted and the ends of the needles are connected to a hot-air source through the medium of a hose, so that the insulating layer can be heated with the aid of hot air. Moist air that diffus¬ es up through the wooden floor surface will be col¬ lected between this surface and the overlying insula¬ tion, where it remained trapped. The described ar- rangement is therefore not very effective. SE-B-454,280 (Tyrens Fδretagsgrupp) describes appara¬ tus for use in buildings which include a bottom slab and an air-permeable drainage layer located beneath the bottom slab for the purpose of reducing high moisture content of the bottom slab, by introducing a volume of air to the drainage layer. This apparatus is not intended to eliminate problems that arise in conjunction with water-damage in buildings, but is intended to ensure that the foundations of a building are brought to a state in which the transport of moisture up into the building is prevented. SE-B-458,696 (Sundolitt) describes a floor insulating layer made of cellular plastic material and presenting hollows or recesses on at least that side thereof which lies proximal to a concrete slab, so as to insulate the floor. The object is to interconnect large surfaces on mutually adjacent sheets so as to achieve effective ventilation and/or drainage along a concrete base slab, particularly when replacing old insulation material while cleaning-up or decontaminat¬ ing mould-damaged flooring. The described plate can only be used in the construction of new buildings and cannot be used in conjunction with drying-out water- damaged buildings. DE-C2-3,043,646 (Munters Trocknungs-Service) describes a concrete floor structure comprising an overlying insulating layer on which there is placed a "floating concrete floor" of known construction. Dry air under pressure is led through a pipe that is inserted in a drill-hole in the "floating floor", down to the insu¬ lating layer and is permitted to depart to the overly¬ ing room through cracks in floor-adjacent walls. The air used shall have a temperature of 30-35°C. The humidity of the air departing from the insulation is measured and the delivery of dry air is terminated when the measured humidity has reached a predetermined value. Similar arrangements and systems have been used for many years, although without having been found partic¬ ularly effective. It can take several weeks or months to effectively dry a water-damaged area when using such arrangements. Further examples of the known prior art having some relevance in the present context are found described and illustrated in publications DE-C2-3,043,646 (Getrow Gebaude Trocknungs GmbH) and DE-A-3,632,424 (Dzigger) . OBJECT OF THE INVENTION One object of the present invention is to provide a drying method of the aforedescribed kind which will enable the energy content of the dry, hot air deliv- ered to a water-damaged area to be recovered more effectively and therewith enable the water-damaged area to be effectively dried more quickly and with a leaner energy input than has hitherto been possible. Another object of the invention is to provide a drying method which will enable the room or space above the water-damaged area to be utilized whilst the drying operation is in progress. According to another aspect, the invention relates to the provision of an arrangement for use in a room or a space in which the floor or sub-floor has been damaged by water and which can be readily transported to the room or space concerned and there installed for the purpose intended with the aid of simple means and which will produce a drying result that is superior to the drying result that has hitherto been possible to achieve at a given energy consumption. SUMMARY OF THE INVENTION These and other objects are fulfilled with an inven¬ tive method of the aforesaid kind which is character- ized by the features set forth in the characterizing clause of Claim 1. The insulation device spaced above the upper floor surface or the sub-floor effectively screens the ener- gy, in the form of the dry-heated air, delivered to the water-damaged area. At the same time, the adapted gap will ensure that the moisture-laden air will diffuse up through the water-damaged floor structure and be carried effectively away, preferably in a manner which will enable a major part of the energy content of the moisture-laden air to be recovered and utilized during the course of the continuously ongoing drying process. According to one preferred embodiment of the inven¬ tion, at least the upper part of the insulation device placed on the floor surface is constructed so as to provide a provisional floor in the overlying room or space, this floor being used as a temporary floor whilst the water-damaged area is being dried. In many cases, the water-damaged area is comprised of an insulating layer, such as a layer of supportive sand, mineral wool or the like, an underlying concrete sub-floor and an upper concrete floor surface. According to one preferred embodiment of the inventive method, one or more holes are formed in the upper concrete floor surface and dry, hot air under pressure is delivered to the layer of sand, mineral wool or the like through one or more separate delivery pipes, and moisture-laden air deriving from the layer of sand, mineral wool or the like is permitted to depart to the room or the space, preferably through cracks in the vicinity of the walls of said room or space, together with moisture-laden transport air. Alternatively, the moisture-laden air can be collected and either carried away or led back to the drying apparatus. This appli¬ cation of the inventive method provides the advantage of heating the upper concrete floor surface from both sides thereof among other things, therewith contributing effectively towards the good drying result obtained when practising the invention. In the case of a preferred method of applying the invention in practice, air is delivered to the room or space, including moisture-laden transport air deliv¬ ered from said gap, and a condenser is used for heat exchange with wet regenerating air which is delivered to the condenser from the outlet of a dehumidifier through a separate condenser inlet, and the formed condensation is collected and led away. The air which is preheated and dried in the condenser is passed to the dehumidifier where moisture is removed from the air and the air is further dried and heated, where¬ after the air is then further heated, pressurized and delivered to said gap by means of at least one blower. According to one embodiment of the invention, part of the blower-heated and blower-pressurized air can be delivered to the layer of sand, mineral wool or the like, through a separate pipe inserted through the upper concrete surface. In practice, it is preferred that the air in the room or space, which may have a temperature of 16-24°C for instance, is delivered to the condenser for heat exchange with wet regenerating air having a tempera¬ ture of 30-60°C, and leaves the dehumidifier at a temperature of 45-50°C, and is then heated to a tem¬ perature of 55-75°C in conjunction with pressurizing the air in at least one high-pressure fan, and then delivered to the gap. The relevant energy levels of the delivered drying air are therewith much higher than can be achieved with conventional drying plants or apparatus, and conse¬ quently the yield afforded by the invention will be much greater than the yield that can be obtained with earlier known methods and apparatus. The inventive apparatus is characterized mainly by the features set forth in the characterizing clause of Claim 7. An exemplifying embodiment of the invention will now be described in more detail with reference to the accompanying schematic drawing, the single Figure of which illustrates in perspective part of a room of a building whose insulated concrete floor has been subjected to water damage. BEST MODES OF CARRYING OUT THE INVENTION The drawing illustrates a room 1 having an upper concrete floor surface 2 which is supported by a concrete sub-floor or floor base 3 and an intermediate insulation layer 4, which may be a layer of sand, for instance. The upper concrete floor surface 2 and the sand layer 4 have been subjected to water-damage, for instance as a result of a leaking pipe. In accordance with the invention, there has been placed in spaced relation¬ ship with the upper concrete surface 2 an insulating device 7 such as to form a gap 8 between the upper concrete surface 2 and the insulating device 7. In the illustrated case, the insulating device 7 is conveniently supported on wooden blocks 9 or the like. Alternatively, the insulating device may be construct¬ ed in a manner which will form gaps, i.e. when the device is placed on a supporting surface, the under¬ side of the device may be given an egg-box configura- tion or may be corrugated or given some like struc¬ ture. The uppermost layer of the insulating device may, for instance, be comprised of laminated boards 7a so as to form a provisional floor surface for temporary use whilst the water-damaged area is being dried. In the case of the illustrated embodiment, dry, hot air under pressure supplied from a high-pressure blower 12 is delivered to the gap 8 through a pipe 13, and to the layer of sand 4 through a further pipe 14. The insulating device 7 ensures that the thermal energy delivered to the gap and to the insulating layer will not be lost. Instead, a substantial part of the energy content of the hot air delivered to the gap 8 is used in drying the upper concrete surface 2. The hot air delivered through the pipe 14 enters the sand layer 4 and heats and dries the moist sand. The upper concrete surface 2 is heated from both sides thereof, therewith contributing towards effective drying of this surface. Moisture-laden air that diffuses through the upper concrete surface 2 enters the gap 8 and is carried away with the aid of the air delivered to the gap through the pipe 13. The air present in the gap and the moisture-laden air deriving from the sand layer 4 depart to the room 1 through cracks 18 located adjacent the walls 19 of the room, as indicated by respective arrows 17 and 16. Alternatively, the moisture-laden air can be collected and then carried away or heated for reuse in the drying operation. The pipe 14 is inserted into the sand layer 4 through holes 2a formed in the upper concrete surface 2. The air present in the room 1, including the moisture- laden transport air delivered through the gap 8, is passed to a condenser/heat exchanger 24 for heat exchange with wet regenerating air which is delivered from the outlet of a dehumidifier 25 to the condenser/ heat exchanger 24 through a hose 26 connected to a separated inlet (not shown) on the condenser/heat exchanger. The condensation formed in the condenser/ heat exchanger is collected and recovered. The room air preheated and dried in the condenser/heat exchanger 24 is delivered to the dehumidifier 25 for dehumidification, where it is further dried and heat¬ ed. This air is then passed through a hose 27 to the inlet of a high-pressure blower 12, in which the air is further heated and also pressurized. Part of this air is delivered through the pipe 13 to the gap 8, whereas another part of the air is deliv¬ ered to the sand layer 4 through the pipe 14. In the case of drying plant or drying apparatus that is intended for practical use, the room air may have a temperature of 16-24°C, preferably about 20°C, and is introduced into the condenser/heat exchanger at this temperature. The wet regenerating air leaving the de¬ humidifier 25 and entering the condenser/heat exchang¬ er 24 through the hose 26 may have a temperature of 30-60°C, preferably about 50°C, and the dry air leaves the dehumidifier at a temperature of about 45-50°C. The air may be heated in the high-pressure fan 12 to a temperature of 55-75°C and is thus delivered to the gap 8 and the sand layer 4 respectively at a tempera- ture which lies roughly within this range, preferably at a temperature of 65°C. The moist air is cooled in the condenser/heat exchanger to practically the same temperature as the room air, and therefore leaves the condenser/heat exchanger at a temperature of about 20°C. The described arrangement enables about 95% of the theoretically possible recoverable energy to be recovered. According to an alternative application of the inven- tion, applied in conjunction with a water-damaged concrete floor structure which does not include an upper insulating layer, such as the sand layer 4 and the upper concrete surface 2, the insulating device 7 can be placed at a distance from the concrete floor so as to leave an intermediate gap corresponding to the gap 8 of the illustrated embodiment. As will be understood, no branch pipe corresponding to the branch pipe 14 is required with this application. In all other respects, the operation is the same as that described above, at least with regard to the drying and transportation processes carried out with the aid of hot, dry air delivered to the gap 8. In practice, the time taken to dry a water-damaged area when practising the described inventive method and using the inventive apparatus is less than about one-quarter of the time required when applying conven¬ tional techniques under otherwise equivalent condi¬ tions. This is partly due to the fact that when treating water-damaged concrete structures in accordance with the invention, the concrete structure will be heated to a temperature of 45-50°C and hence the water pres- ent therein will "boil-off" as a result of the high energy content of the dry, hot air delivered to the concrete construction. It will be obvious to one of normal skill in this art that the inventive concept can be applied in ways other than those described while remaining in the scope of the invention as defined in the following Claims.

Claims: CLAIMS 1. A method of drying a water-damaged concrete floor or concrete sub-floor, which possibly includes an insulating layer, wherein pressurized dry, hot air is delivered to the water-damaged area and moisture- saturated air is allowed to depart to atmosphere, to an overlying room or space, or is collected and car¬ ried away or treated and optionally reused, c h a r a c t e r i z e d by placing an insulating device across the floor or the sub-floor surface in spaced relationship therewith so as to form a gap between said surface and the insulating device; and introducing the pressurized dry, hot air into the gap with the intention of carrying moisture-laden air away from the water-damaged area. 2. A method according to Claim 1, c h a r a c t e - r i z e d by constructing at least the upper part of the insulating device so that the device can be used as a temporary floor in the overlying room or space while the water-damaged area is being dried. 3. A method according to Claim 1 or 2, wherein the water-damaged area includes an insulating layer of, for instance, sand, mineral wool or the like and an upper concrete surface supported on a concrete con¬ struction, c h a r a c t e r i z e d by forming one or more holes in the upper concrete surface, delivering dry, pressurized hot air through one or more separate delivery pipes down into the layer of sand, mineral wool or the like, and by allowing moisture-laden air deriving from the layer of sand, mineral wool or the like to depart to the room or space together with moisture-laden transport air, conveniently through cracks present adjacent the walls of the room or space. 4. A method according to any one of Claims 1-3, c h a r a c t e r i z e d by introducing air present in the room or space, including moisture-laden trans¬ port air deriving from said gap, to a condenser/heat exchanger for heat exchange with wet regenerating air, said air being delivered to the condenser/heat exchanger from the outlet of a dehumidifier and through a separate condenser/heat exchanger inlet, while collecting and removing the condensation formed; delivering the preheated and dried air from the room to the dehumidifier for dehumidification and further drying and heating of the air; and thereafter further heating and pressurizing the air in at least one blower means and delivering the air to the gap. 5. A method according to Claim 4, c h a r a c t e - r i z e d by delivering part of the air heated and pressurized in the blower means to the layer of sand, mineral wool or the like through a separate pipe passing through the upper concrete surface. 6. A method according to Claim 5, c h a r a c t e ¬ r i z e by passing room air, at a temperature of about 16-24°C, to the condenser/heat exchanger for heat exchange with wet regenerating air having a temperature of about 30-60°C, wherein the air leaves the dehumidifier at a temperature of about 45-50°C and is then heated to a temperature of 55-75°C by pressur¬ izing the air in at least one high-pressure blower means, whereafter the thus heated and pressurized air is delivered to said gap. 7. Apparatus for drying a water-damaged concrete floor or concrete sub-floor, possibly including an insulation, comprising means (12, 13) for delivering hot, dry pressurized air to the water-damaged area (2, 3, 4), and means whereby moisture-saturated air can depart to atmosphere or to an overlying room or space (1) , c h a r a c t e r i z e d by an insulating device (7) which is placed over the floor (2) or the sub-floor (3, 4) in a manner to form a gap (8) between said insulating device and the floor or sub-floor surface; and means (12, 13) for delivering the hot, dry air to the gap (8) with the intention of carrying moisture- laden air away from the water-damaged area. 8. Apparatus according to Claim 7, c h a r a c t e ¬ r i z e in that at least the upper part of the insulating device (7) is constructed to provide a provisional floor in the overlying room (1) , for temporary use while the water-damaged area is being dried. 9. Apparatus according to Claim 7 or 8, wherein the water-damaged area includes a structural concrete layer or sub-floor (3) , a layer (4) of sand, mineral wool or the like, for instance, supported by said constructional concrete layer, and an upper concrete surface (2), c h a r a c t e r i z e d by means (14) for delivering hot, dry air to the insulating layer (4). 10. Apparatus according to Claim 9, c h a r a c t e ¬ r i z e by a room-mounted condenser/heat exchanger (24) for heat exchange with wet regenerating air from a dehumidifier (25) , said regenerating air being intended for supply to the condenser/heat exchanger through a separate inlet; and in that hot air deliv¬ ered by the dehumidifier (25) is delivered to a fan means (12) through a conduit (27) , where the air is pressurized and further heated, wherein said fan also has connected thereto means (13) for delivering trans¬ port air to the gap (8) .

Inventors: CLAESSON KNUT, HOLMQUIST OLA, CLAESSON, KNUT, HOLMQUIST, OLA
Applicants: CLAESSON KNUT, HOLMQUIST OLA, RENTOVENTA AB, CLAESSON, KNUT, HOLMQUIST, OLA
Application year: 1994
Main classification: E04B1
IPC codes: E04B1